Description of arch reflex

Question

Give a brief description of arch reflex?

Answer 1

In some conditions the movement of skeletal striated muscles doesn’t depend upon commands of superior motor neurons, that is, it is not triggered by the volition.

Involuntary movements of those muscles might take place when sensory fibers which create direct or indirect connection with inferior motor neurons are unpredictably stimulated in condition that suggests danger to body. This takes place, for illustration, in patellar reflex, knee jerk reflex, when an unexpected percussion on knee patella (kneecap) triggers an involuntary contraction of quadriceps (extension muscle of thigh). Another illustration of arch reflex takes place when someone steps on a sharp object: one leg retracts and other, by arch reflex, distends to controls the equilibrium of body.